This invention relates generally to calibration of devices and, more particularly, to the use of flexible mechanical limiters to locate a rotational sensor for automatically calibrating devices in high impact environments.
Rotational sensors are used to provide rotation measurements of many different devices, including those that sustain impacts, such as joystick gimbals, shifter paddles, steering wheels, brake and accelerator pedal assemblies, and the like. An input device may have a full design travel for the rotational sensor to measure during normal operation or play. During aggressive operation or play, however, the travel may exceed the full design travel of the device, and the device is automatically calibrated. The load or force typical of normal operation will be unable to achieve the full design travel because the input device has been automatically calibrated to a larger travel during aggressive operation or play.
Embodiments of the present invention are directed to preventing calibration of an input device to exceed the full design travel, for instance, during aggressive operation or play. A limiter is coupled to the rotational sensor to limit the full travel output signal to a fixed and repeatable maximum value no matter how aggressive the operation or play becomes. The limit is desirably set at such a point as normal operation or play will always reach. In this way, the automatic calibration of the input device will not exceed the full design travel.
In accordance with an aspect of the present invention, an input device comprises a user manipulable object configured to rotate around a rotational axis relative to a base. A rotational sensor includes a sensor body coupled with a sensor shaft which is rotatable relative to the sensor body around the rotational axis. The sensor shaft is connected with the user manipulable object to rotate with the user manipulable object around the rotational axis. An actuator is coupled with the user manipulable object to rotate with the user manipulable object. The actuator is configured to be coupled with the sensor body, after the user manipulable object has rotated to reach a preset limit, to rotate the sensor body with the sensor shaft and the user manipulable object beyond the preset limit.
In some embodiments, a mounting mechanism is coupled with the rotational sensor to permit movement of the sensor body with the sensor shaft except in rotation with respect to the rotational axis in at least one of a clockwise direction and a counterclockwise direction which is constrained by the mounting mechanism. The sensor body includes a protrusion. The mounting mechanism comprises a first surface provided on the base and being disposed generally laterally relative to the rotational axis and contacting a first side of the protrusion to constrain rotation of the sensor body around the rotational axis in a first direction which is a clockwise or a counterclockwise direction. The mounting mechanism comprises a second surface provided on the base and being disposed generally laterally relative to the rotational axis and contacting a second side of the protrusion to constrain rotation of the sensor body around the rotational axis in a rotational direction opposite from the first direction. The protrusion of the sensor body includes a generally spherical distal end and the first surface contacts the generally spherical distal end to permit movement of the sensor body with the sensor shaft except rotation of the sensor body around the rotational axis which is constrained by the first surface. The first surface of the mounting mechanism comprises a spring.
In specific embodiments, the sensor shaft of the rotational sensor is substantially immovably connected to the user manipulable object to move with the user manipulable object. The actuator comprises a pair of actuator arms disposed on opposite sides of the sensor body. The user manipulable object comprises a pedal having a pedal bushing which is rotatably supported on the base to rotate around a pedal bushing axis. The sensor shaft extends into a pedal bushing aperture along the pedal bushing axis.
In accordance with another aspect of the invention, an input device comprises a user manipulable object configured to rotate around a rotational axis relative to a base. The user manipulable object has an aperture configured to receive a sensor shaft of a rotational sensor to rotate the sensor shaft with the user manipulable object relative to the sensor body around the rotational axis. An actuator is coupled with the user manipulable object to rotate with the user manipulable object. The actuator is configured to be coupled with the sensor body, after the user manipulable object has rotated to reach a preset limit, to rotate the sensor body with the sensor shaft and the user manipulable object beyond the preset limit.
In some embodiments, the mounting mechanism comprises a spring having at least one contact surface to contact the sensor body and constrain rotation of the sensor body around the rotational axis in at least one of a clockwise direction and a counterclockwise direction. The actuator comprises a pair of actuator tabs disposed on opposite sides of the aperture of the user manipulable object and configured to be coupled with the sensor body on opposite sides of the sensor body.
Another aspect of the present invention is directed to a method of limiting travel of a rotational sensor for an input device to a preset limit. The method comprises connecting a sensor shaft of a rotational sensor to a user manipulable object of an input device which is configured to rotate with the sensor shaft around a rotational axis relative to a base; mounting a sensor body of the rotational sensor to permit movement of the sensor body with the sensor shaft except rotation with respect to the rotational axis which is constrained; and, after the user manipulable object has rotated to reach a preset limit, coupling the sensor body to the user manipulable object to rotate with the user manipulable object and the sensor shaft beyond the preset limit.
In some embodiments, after the user manipulable object has rotated to reach a preset limit, the sensor body is coupled to the user manipulable object to rotate with the user manipulable object and the sensor shaft beyond the preset limit in the clockwise direction at one end of the preset limit and in the counterclockwise direction at another end of the preset limit.